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Ancient natural nuclear reactors show how to store radioactive waste

We’ve got to store it somewhere

Krisztian Bocsi/Bloomberg via Getty Images

By Leah Crane

Earth’s crust used to be full of radioactive uranium. In some spots, conditions were right for that uranium to undergo chain fission reactions – the same reactions that give us nuclear power today. Now, the remnants of these natural nuclear reactors are helping us figure out how best to store modern radioactive waste.

When the isotope uranium-235 is struck by relatively slow-moving neutrons, it breaks apart into smaller elements in a fission reaction, releasing huge amounts of energy. Uranium-235 has a half-life of 700 million years …